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The Coordination Behavior of Oxygen‐depleted Calixarenes towards d 10 Noble Metal Ions
Author(s) -
Keck Matthias,
Hoof Santina,
Rawat Varun,
Vigalok Arkadi,
Limberg Christian
Publication year - 2020
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.202000138
Subject(s) - chemistry , denticity , ligand (biochemistry) , calixarene , steric effects , metal , copper , metal ions in aqueous solution , crystallography , coordination sphere , ion , medicinal chemistry , stereochemistry , inorganic chemistry , molecule , organic chemistry , receptor , biochemistry
A calix[4]arene, in which two of the phenol functions are replaced by pyrazole units, [H 2 (bpzCal)], was investigated as a ligand for Cu + , Ag + and Au + ions. Using [Cu(MeCN) 4 ]BF 4 and AgSbF 6 as the precursors, complexes [MH 2 (bpzCal)]X (M = Cu, X = BF 4; M = Ag, X = SbF 6 ) were formed, where the calixarene ligands adopt a 1,3‐alternate structure and the metal ions are coordinated linearly by the two pyrazolyl donors. [CuH 2 (bpzCal)]BF 4 displayed a – for copper(I) complexes – unusual stability towards O 2 , which is due to the steric protection of the Cu I center. By contrast a dinuclear copper(I) complex [Cu 2 (bpzCal)] that was obtained through treatment of [H 2 (bpzCal)] with two equivalents of Cu(HMDS) is rather sensitive towards O 2 . The preparation of a gold complex required the employment of a gold precursor, which contains one labile and one stabilizing neutral ligand, namely [(PPh 3 )Au(NCMe)]SbF 6 , which led to the formation of [(PPh 3 )AuH 2 (bpzCal)]SbF 6 . In this complex [H 2 (bpzCal)] acts only as a monodentate ligand for the gold center. Taken together, the results demonstrate the potential of [H 2 (bpzCal)] in providing rather different coordination spheres for metal ions.